Precise Coil Alignment for Dynamic Wireless Charging of Electric Vehicles with RFID Sensing

Electric vehicle (EV) has emerged as a transformative force for the sustainable and environmentally friendly future. To alleviate range anxiety caused by battery and charging facility, dynamic wireless power transfer (DWPT) is increasingly recognized as a key enabler for widespread EV adoption, yet it faces significant technical challenges, primarily in precise coil alignment. This article begins by reviewing current alignment methodologies and evaluates their advantages and limitations. We observe that achieving the necessary alignment precision is challenging with these existing methods. To address this, we present an innovative RFID-based DWPT coil alignment system, utilizing coherent phase detection and a maximum likelihood estimation algorithm, capable of achieving sub-10 cm accuracy. This system's efficacy in providing both lateral and vertical misalignment estimates has been verified through laboratory and experimental tests. We also discuss potential challenges in broader system implementation and propose corresponding solutions. This research offers a viable and promising solution for enhancing DWPT efficiency.